Enhancing mobile services with DVB-S2X superframing

N. Mazzali, S. Boumard, J. Kinnunen, B. Shankar M. R., M. Kiviranta, N. Alagha
2018 International Journal of Satellite Communications And Networking  
DVB-S2X is the cornerstone for satellite communication standards forming the state-of-the-art of broadband satellite waveforms. In this paper we propose new application scenarios and advanced techniques, including a reference design implementing superframing, predistortion, a robust synchronization chain, and a plugand-play channel interleaver. We demonstrate by means of software simulations and hardware tests that the DVB-S2X can be a common technology enabler for land-mobile, aeronautical,
more » ... maritime satellite scenarios in addition to the more traditional VSAT scenario, even in very challenging conditions (e.g., very low SNR). Prepared using satauth.cls [Version: 2010/05/13 v2.00] 2 N. MAZZALI ET AL. starting point for the presented investigation. The biggest demand for the extensions of the DVB-S2 standard came from video contribution and high-speed Internet protocol (IP) services, as these services are affected the most by the increased data rates. Naturally, many of the features included in the DVB-S2X standard target these applications and some gains (in terms of spectral efficiency) over DVB-S2 are reported in [3] . The relevant reference markets for DVB-S2X include television broadcasting, interactive services, and professional links [3] . Data content distribution / trunking and other professional applications are mainly point-to-point or point-to-multipoint, including interactive services to professional head-ends, which redistribute services over other media. Such services are characterized by their ability to distinguish receivers based on contents, different quality-of-service targets, and reception capability with consumer-sized antennas. Mobile services and applications have been partly addressed by the DVB-S standard for hand-held terminals (DVB-SH) [4]. Nevertheless, the widespread diffusion of DVB-SH has been significantly delayed by many factors, for example the needed integration between satellite and terrestrial infrastructures [4]. Mobile services remain therefore one of the most appealing emerging markets for satellite operators and service providers. Indeed, broadband data services to land-mobile systems are gathering momentum, as well as broadband and telemetry for aeronautical services. Since its inception, the DVB-S2X standardization activity has aimed at a performance improvement following either an evolutionary or a revolutionary path. For example, [5] focused on techniques and technologies that may potentially enhance different aspects of satellite communications, namely the achievable spectral efficiency on the satellite channel, as well as the system flexibility and complexity. In particular, the considered technologies include new modulation and coding schemes, new waveforms (e.g., single-carrier orthogonal frequency-division multiplexing, time-and-frequency packing), new algorithms for joint detection, decoding, and equalization, interference mitigation and multiple-input multiple-output (MIMO) systems, framing and pilot optimization. Today, the performance of the state-of-the-art waveforms are very close to the theoretical upper limit [3]. Since a significant performance gain cannot be achieved by means of advanced signal processing techniques [5], the key strategy to improve the satellite services and expand the satellite market is identifying new applications based on existing air interfaces along with additional processing (such as predistortion and channel interleaving) to provide significant gain over the currently deployed waveforms. In this perspective, professional mobile applications are prime targets. DVB-S2X provides optional functionalities that have not been exploited much so far. Namely, superframing has only been considered to improve synchronization [6] and for interference mitigation purposes [7] . In this paper, we will consider one of the superframe formats described in the DVB-S2X standard [2] and will show how it is instrumental to reliable communications in mobile scenarios. A special attention in the design phase of the system is given to the main impairments affecting satellite mobile communications, namely the nonlinear distortion introduced by the satellite transponder, the correlated fading generated by the propagation channel, the Doppler shift stemming from the mobility of the terminal, and the possibly very low SNR (VL-SNR). To cope with them a predistorter, a plug-and-play self-synchronizing channel interleaver, and a hardwarefriendly yet robust synchronization chain were designed and tested. Finally, in order to assess the suitability of DVB-S2X for realistic mobile applications, a hardware testbed was implemented and This scenario deals with broadband interactive services enabled by VSAT configurations and also addresses a core market of DVB-S2. ETSI defines VSAT as a one-way (e.g., a large number of VSATs in US are used for broadcasting) or two-way (interactive) terminal used in a star, mesh, or point-to-point network. While the star network invariably entails a large performance hub station, mesh networks with terminals having similar performance are also present. Figure 1 depicts a typical Inmarsat VSAT network. Particularly, the VSAT terminals SAT1-4 are served by beam A and have varying antenna configurations; SAT5 is served by beam B; further, SAT3 acts as the controller of the network with terrestrial links to all the terminals. Finally, the beams could be in L-and Ku-bands.
doi:10.1002/sat.1255 fatcat:2vxgyv2iejcvbchls5bluujuhi